Julia Roberts and Betty Lou Motes Julia Roberts and Betty Lou Motes

Julia Roberts' mother, Betty Lou Motes, died Thursday at St. John's Health Center in Santa Monica, Calif., In Touch reports. She was 80.

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Motes was reportedly battling lung cancer, and was living in Los Angeles with Roberts, her husband Danny Moder, and their three children. An email to a rep for Roberts was not immediately returned.

Just over a year ago, Motes' daughter and Roberts' half-sister Nancy committed suicide.

Throughout Roberts' acting career, Motes had occasionally accompanied her daughter to fundraisers and red carpet events.